And in Arcadia by Catja Mikhailovic (Fred/George, George/Ginny). I don't think I've ever quoted lines from the stories I've rec'd, but the first two of this one are too good of a hook not to:
Fred and George would say that each is something separate from the other; the difference is that Fred actually believed it. It was easier for him, since he came first and could be considered the template. George was an afterthought, a part of Fred that simply happened not to be permanently attached to his body.And really, it just gets better from there.